Surgical fastening device

ABSTRACT

A surgical instrument for placing fasteners and/or a reinforcement material in tissue is provided. Structure is provided for advancing the fasteners distally by an actuating handle means working in concert with a pusher means. The fasteners exit the fastener housing at an angle to the longitudinal axis of the device to facilitate visualization and placement at the surgical site. A unique fastener may be formed in which the legs are in a substantially overlapping longitudinally-spaced relation.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of commonly assigned,copending U.S. patent application Ser. No. 07/696,511, filed May 7,1991.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a device for applying clips or staplesto tissue, and more particularly to a unique delivery system adapted forendoscopic application of clips/staples. The system is useful forrepairing defects in the body wall, e.g., by securing a mesh to the wallin the region of the defect.

2. Background of the Invention

The placement of clips and staples in surgical procedures is well known.For example, U.S. Pat. Nos. 4,616,650 to Green et al. and 4,934,364 toGreen disclose clip appliers for placing clips, both absorbable andnon-absorbable, on tissue and vessels. The clips are fed successivelyinto the instrument jaws and cammed closed. Instruments for placing aplurality of staples on tissue and optionally cutting therebetween aredisclosed in U.S. Pat. Nos. 3,494,533 to Green et al. and 4,520,817 toGreen. The staples are supplied in pre-loaded cartridges and are formedthrough contact with oppositely positioned anvil pockets.

An important consideration in the design and utilization of surgicalclip appliers and staplers is the visibility and ease of instrumentpositioning provided to the surgeon. One approach has been to provide astapler having a fastener applying assembly that articulates relative tothe actuator assembly, as disclosed in U.S. Pat. Nos. 4,566,620 and4,728,020 to Green et al. It has also been suggested to provide asurgical clip applier with a longitudinally curved sleeve, as disclosedin U.S. Pat. Nos. 4,509,518 and 4,624,254 to McGarry et al., and4,664,305 to Blake.

Instruments for surgically stapling disunited skin of a patient toeffect joining of the skin are also known. These instruments typicallyform substantially box-shaped staples by bending each staple around ananvil placed against the skin, and may be adapted to permit rotation ofthe staple forming assembly relative to the handles. See, e.g., U.S.Pat. Nos. 3,643,851 to Green et al. and Re. 28,932 to Noiles et al.Fascia staplers have also been disclosed which form fascia stapleshaving a unique geometry for holding fascia tissue. See, e.g., U.S. Pat.No. 4,127,227 to Green.

More recently, attention has focused on minimally-invasive surgicalprocedures and instruments for facilitating such procedures.Minimally-invasive procedures are typically performed endoscopicallythrough trocar sleeves or cannulas. Prior to introducing the cannulathrough the body wall, the surgeon generally insufflates the body cavitywith carbon dioxide, e.g., through a Verres needle or like device.Insufflation creates a free area between internal body organs and thebody wall. The surgeon then introduces one or more trocars through thebody wall in to the insufflated body cavity to create a port of entryfor accessory instrumentation. For example, graspers, dissectors, clipappliers, lasers and electrocautery devices are routinely employedendoscopically with the visual assistance of an endoscope and anexternal television monitor.

Endoscopic cholecystectomy (gall bladder removal) has recently met withtremendous clinical success and acceptance. Another procedure receivingattention for adaptation as a minimally-invasive surgical technique ishernia repair, with attention being primarily directly to all types ofinguinal hernias (direct, indirect and femoral). A hernia involves theprotrusion of an inner organ or body part through a defect in the musclewall by which it is ordinarily contained. Historically, hernia repairhas been performed by pulling the muscles together around the defect andsuturing the muscles together, closing the hole but creating tension onthe sutures. More recently, hernia defects have been repaired bysuturing mesh over the defect. This approach patches the defect ratherthan drawing the spaced muscle walls together and/or ligating the herniasac.

In order to facilitate surgical procedures, and particularly endoscopicprocedures such as hernia repair, instrumentation is needed whichprovides the surgeon with improved visibility and which facilitatespositioning of the instrument at the surgical site. A fastening systemto provide optimal securement of a mesh or like device, preferablyendoscopically, is also needed. These and other objectives are achievedby the present invention.

SUMMARY OF THE INVENTION

In accordance with the present invention, a surgical instrument forplacing fasteners in or on tissue is provided which includes:

(a) a fastener housing having anvil means mounted at one end thereof andadapted to house at least one fastener therein;

(b) pusher means slidably received by said fastener housing, the pushermeans comprising a pusher bar which defines a longitudinal axis and apusher element slidably mounted to the pusher bar; and

(c) slot means in the fastener housing, wherein the pusher meanscooperates with the slot means to angularly displace the pusher elementwith respect to the longitudinal axis as the pusher means is advancedthrough the fastener housing.

The surgical instrument of the invention is thus adapted to angularlydeliver a fastener to tissue with respect to the longitudinal axis ofthe instrument. Such angular delivery provides improved visibility tothe surgeon and facilitates fastener placement in difficult tissuelocations. The instrument is particularly suited for endoscopicapplications, e.g., for securing a mesh to tissue in hernia repair.

In a preferred embodiment, the fastener housing contains a plurality offasteners for sequential placement in tissue. Means are provided foradvancing the fasteners distally and further means are provided forpreventing more than one fastener from being placed in the "ready"position. A fastener may be placed by actuating handle means, e.g., apistol handle, which effects distal movement of the pusher means. Thefastener housing is preferably rotatable with respect to the handlemeans to further facilitate visibility and fastener placement.

According to the present invention, fasteners are angularly delivered totissue through cooperation between slot means, pin means and cam means.The pusher element includes a contact face which is adapted to advance afastener into engagement with and formation against the anvil means. Thepusher element travels within a fastener track in the fastener housing,the width of which is only slightly larger than the width of the pusherelement contact face. The pusher element is slidably mounted to thepusher bar by pin means extending through a transverse slot formed atthe distal end of the pusher bar. Further slot means are formed in thefastener housing below the pusher bar. The pin means extends through thetransverse slot to ride within the fastener housing slot means.

The fastener housing slot means causes the pusher element to jog asfollows:

(i) the fastener housing slot means includes a first slot region whichextends along the longitudinal axis of the instrument; the contact faceof the pusher element is substantially perpendicular to the longitudinalaxis of the instrument as the pin means travels within the first slotregion;

(ii) distal to the first slot region, a second slot region communicateswith and is angular oriented with respect to the first slot region;inasmuch as the pusher element is constrained in its transverse movementby the fastener track, as the pin means enters the second slot regionthe pin means moves within the transverse slot formed in the pusher barand the pusher element rotates with respect to the pusher bar; and

(iv) a third slot region communicates with the second and extends at anangle to the longitudinal axis of the instrument opposite to that of thesecond slot region; as the pin means enters the third slot region thepusher element is prevented from returning to its initial non-rotatedorientation through contact with a cam face extending into the fastenertrack; thus, as the pin means moves back within the transverse slot, thepusher element retains its rotated position with respect to the pusherbar.

A unique fastener-forming assembly is also provided according to thepresent invention which includes:

(a) a fastener housing defining a fastener track having a center lineand an opening at one end adapted to permit fastener exit;

(b) anvil means positioned adjacent the exit opening, the anvil meansbeing positioned in a transverse and non-symmetrical orientation withrespect to the center line; and

(c) a fastener having a backspan and a pair of legs extending from thebackspan at either end thereof; wherein contact of the fastener with thenon-symmetrically positioned anvil causes the backspan of the fastenerto bend such that the fastener legs assume a substantially over-lapping,longitudinally-spaced relation.

The fastener-forming assembly of the invention facilitates formation ofa fastener particularly suited for securing an article, e.g., areinforcement mesh, to tissue, as for example in hernia repair. Theover-lapping configuration of the formed fastener allows the fastenerlegs to advance further than prior art fasteners prior to bending, thusfacilitating fastener placement. Moreover, the substantiallyover-lapping, longitudinally-spaced orientation of the fastener legsprovides excellent holding power when embedded in tissue. Preferably,the means for advancing the fastener into contact with the anvil meanscomprises a U-shaped pusher element having legs of differing widths soas to cooperate with the non-symmetrically positioned anvil means.

The instruments of the present invention are specifically suited forendoscopic applications. In such cases, the fastener formation system istypically fabricated as part of an endoscopic portion which is adaptedfor introduction through a trocar sleeve having a diameter of, forexample, 10 to 15 mms. Internal sealing means are typically provided inthe instrument, e.g., a sealing block, to ensure a gaseous seal whenworking in an insufflated body cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures referred to herein and constituting a parthereof illustrate preferred embodiments of the present invention, andtogether with the description, serve to explain the principles of theinvention.

FIG. 1 is a schematic plan view of a distal portion of a fastenerhousing according to the present invention;

FIG. 2 is a top view of a portion of a pusher bar;

FIG. 3 is a front view of a pusher element of the invention;

FIG. 4 is a bottom view of the pusher element;

FIG. 5 is a schematic view of a preferred, formed fastener;

FIG. 6 is a schematic plan view of a distal portion of the fastenerhousing of FIG. 1 at various stages of fastener advancement;

FIG. 7 is a perspective view of an endoscopic surgical instrumentaccording to the present invention;

FIG. 7a is a perspective view of a portion of the surgical instrumentshown in FIG. 7 being rotated.

FIG. 8 is an exploded perspective view of a handle section of theendoscopic surgical instrument shown in FIG. 7;

FIG. 9 is a perspective view of a rotatable nose assembly of theendoscopic surgical instrument shown in FIG. 7;

FIG. 10 is an enlarged cross-sectional view taken along lines 10--10 ofFIG. 7 illustrating the mechanism at the proximal end of the instrumentfor providing controlled distal movement to advance and to closefasteners at the distal end;

FIG. 11 is an enlarged cross-sectional view of the pawl an ratchetsystem in the handle section which prevents proximal movement of thefastener advancing system after distal movement has begun;

FIG. 12 is a view similar to FIG. 11 illustrating the pawl and ratchetsystem of FIG. 11 after a fastener has been fired and during theproximal movement of the firing mechanism; and

FIG. 13 is an exploded perspective view illustrating the elongatedendoscopic portion of the endoscopic surgical instrument shown in FIG.7.

DETAILED DESCRIPTION OF THE INVENTION

A variety of actuation and fastener feeding mechanisms may be employedto advance the pusher means of the surgical instrument of the presentinvention to form and place fasteners. For example, the principles ofthe present invention may be adapted for use with a variety of handleconfigurations, e.g., pistol grips, scissor grips, palm grip, etc.Similarly, the fasteners of the invention may be stored and individuallyplaced in the "ready" position using a variety of known mechanisms.Illustrative of such mechanisms are the pinion gear/pinion shaftmechanism and related structure disclosed in Re. 28,932 to Noiles etal., the belt mechanism and related structure disclosed in U.S. Pat. No.3,837,555 to Green, and the mechanism and related structure of U.S. Pat.No. 4,204,623 to Green. The contents of these three commonly assignedU.S. patents are hereby incorporated by reference.

The present invention may be fabricated as a single, unitary assemblyintended for single or multiple use, or practiced in association with areusable actuating assembly which is adapted to receive a plurality ofpre-loaded cartridges, whether in a single surgical procedure or, aftersterilization, in further procedures. Such choices are well within theskill of one of ordinary skill in the art and are deemed to be withinthe scope of the present invention.

The following description shall be directed to fastener advancement andformation from the point at which a single fastener has been placed inthe "ready" position, i.e., positioned adjacent pusher means adapted toadvance the fastener into contact with the anvil means. As noted above,a variety of mechanisms and structure may be employed to position afastener in the ready position.

With reference to FIG. 1, a schematic plan view of the fastener housingin the region of fastener delivery is provided. Fastener housing 10includes a fastener track 12 which extends substantially along thelongitudinal axis of fastener housing 10. Fastener track 12 is definedby track walls 14, 15. Fastener track 12 is sized and dimensioned toreceive an unformed fastener 44, as discussed hereinbelow.

A slot 18 is formed in fastener track 12 toward the distal end offastener housing 10. Slot 18 comprises first slot region 20, second slotregion 22 and third slot region 24. First slot region 20 extendssubstantially along the longitudinal axis of fastener housing 10 whichis opposite to the angle of second slot region 22. Although, asillustrated, first and second slot regions 22, 24 are linear, a varietyof geometries are possible, as for example arcuate slot paths.

An anvil 26 is positioned adjacent the outlet of fastener track 12.Anvil 26 is spaced from the termination of slot 18. Anvil 26 comprises arigid material, e.g., stainless steel, which is sized and dimensioned tofacilitate fastener formation therearound. Although FIG. 1 shows asingle anvil 26 positioned in fastener track 12, additional anvil meansare contemplated for incorporation into the instrument of the presentinvention, as for example the dual anvil sections (106,108) of U.S. Pat.No. 4,127,227 to Green, previously incorporated by reference.

The distal end 28 of fastener housing 10 includes an angled face 30which is at an Angle A to the transverse axis of fastener housing 10.Angle A of angled face 30 is generally about 5° to 45° and preferably15° to 25° relative to the transverse axis of fastener housing 10. AngleA may be less than 45° or greater than 5° by making appropriateadjustments to slot 18 and fastener track walls 14, 15, as discussedbelow.

Fastener track wall 14 forms an inwardly directed cam face 32 at itsdistal end. A corresponding, outwardly directed wall section 34 isformed at the distal end of track wall 15. By "inwardly" and "outwardly"directed is meant toward and away from the center line of fastener track12, respectively. Cam face 32 and wall section 34 are preferably at anAngle B to the longitudinal axis of fastener housing 10. Angles A and Bare preferably substantially equal.

Inwardly directed cam face 32 and outwardly directed wall section 34cause fastener track 12 to angle with respect to the longitudinal axisof fastener housing 10. The width of fastener track 12 remainssubstantially constant throughout, i.e., in both its longitudinallyoriented and angled regions. Third slot region 24 is typically at thesame angle to the longitudinal axis as cam face 32 and wall section 34,i.e., Angle B. Anvil 26 is positioned transverse to the angled region offastener track 12.

Referring to FIG. 2, an elongated pusher bar 38 is slidably receivedwithin fastener track 12. Pusher bar 38 includes a transverse slot 40 atits distal end. Transverse slot 40 is asymmetric with respect to thecenter line of pusher bar 38. The proximal end 42 of pusher bar 38 isadapted to cooperate with an actuating mechanism which effectuateslongitudinal movement of pusher bar 38 within fastener track 12 toadvance and form a fastener 44.

As shown in FIGS. 3 and 4, a U-shaped pusher element 46 includes adownwardly extending pin 48. Pusher element 46 also includes a contactface 50 which includes distally pusher legs 52, 54 and a substantiallyU-shaped region 56. Side wall 58 includes a longitudinally directed sideface 60 and angled abutment face 62. Pin 48 is sized and dimensioned toextend through and ride with transverse slot 40 in pusher bar 38, and tofurther extend into and ride within slot 18 in fastener track 12.

Referring to FIG. 6., the interaction and cooperation of pusher bar 38,pusher element 46, fastener track 12, slot 18 and anvil 26 will now bedescribed. FIG. 6 shows the above elements at various stages of fasteneradvance. Fastener 44 is positioned distal of and in abutment withcontact face 50 of pusher element 46. In the proximal-most position ofpusher element 46, pin 48 is located within first slot region 20 andwithin transverse slot 40 to substantially the center line of pusher bar38.

As the pusher bar 38 is advanced distally, pin 48 enters second slotregion 22 which causes pin 48 to travel within transverse slot 40 towardtrack wall 14. Contact between side face 60 of pusher element 46 andtrack wall 14 prevents transverse displacement of pusher element 46 withrespect to fastener track 12 and causes counterclockwise rotation ofpusher element 46 around pin 48. This counterclockwise rotation bringsangled abutment face 62 into contact with track wall 14 (pusher element46 is illustrated just prior to complete rotation). Contact face 50 ofpusher element 46 thus assumes an angled orientation with respect to thelongitudinal axis of fastener housing 10. Fastener 44 is brought in thesame angled orientation through interaction with contact face 50.Contact face 50 and fastener 44 are preferably oriented at an Angle B tothe longitudinal axis of fastener housing 10.

Further distal movement of pusher bar 38 causes pin 48 to enter thirdslot region 24. A pin 48 reaches third slot region 24, side wall 58 ofpusher element 46 comes into contact with inwardly directed cam face 32.Pin 48 travels within transverse slot 40 toward track wall 15 as itmoves distally within third slot region 24. Fastener 44 is thus advancedthrough the angled portion of fastener track 12. Backspan 64 of fastener44 engages anvil 26 and pusher legs 52, 54 drive fastener 44 so as tobend fasteners legs 66 therearound (see also FIG. 5). Fastener 44 isfully formed at such time as pin 48 reaches the distal termination ofslot 18.

In use, the surgeon places angled face 30 of fastener housing 10adjacent to or against the tissue, reinforcement material or the like,to be fastened. The surgeon may, if he wishes, advance pusher bar 38 andthus fastener 44 to expose fastener legs 66 from fastener housing 10prior to so placing fastener housing 10, to facilitate proper placementof fastener 44. Thereafter, pusher bar 38 is advanced to form fastener44 in or around the tissue and/or reinforcement material, e.g., mesh, tobe fastened.

In a preferred embodiment of the invention, fastener 44 is formed in aunique configuration which provides significant clinical advantages,particularly when used to fasten a reinforcement material to tissue,e.g., in hernia repair. The unique fastener configuration isaccomplished by (i) positioning anvil 26 asymmetrically with respect tothe center line of the angled portion of fastener track 12 and (ii)providing a pusher member 42 adapted to cooperate with asymmetricallypositioned anvil 26 and preferably including contact legs 52, 54 ofdiffering widths. In forming this unique fastener 44, the surgeon isable to expose greater lengths of fastener legs 66 to facilitatevisualization and optimal placement because, when formed, legs 66 assumea substantially overlapping, longitudinally-spaced relation.

Referring to FIGS. 3, 4 and 6, contact leg 52 of pusher member 42 has agreater width than contact leg 54. Anvil 26 is positioned asymmetricallywith respect to the center line of the angled portion of fastener track12, being positioned more toward the side on which thinner contact leg54 travels.

As pusher member 42 approaches anvil 26, contact legs 52, 54 pass oneither side thereof. Fastener 44 is thus bent into the configurationshown in FIG. 5, with legs 66 in substantially overlapping,longitudinally-spaced relation. The arcuate travel of legs 66 as theyare bent into their final configuration provides an advantageous biteinto tissue and/or reinforcement material, and the overlapping,longitudinally-spaced relation provides excellent holding power.Preferably fastener legs 66, when formed, are in a substantiallyparallel orientation, although the exact degree to which fastener legs66 are parallel will generally depend on the resilience of the substrateinto which they are fastened.

Referring to FIGS. 7 and 7a there is illustrated a preferred embodimentof the present invention particularly adapted for endoscopic applicationof surgical fasteners. The fastener housing 10 is preferablyincorporated at the distal end of an endoscopic surgical instrument 70.More specifically, the endoscopic surgical instrument 70 preferablyincludes an elongated endoscopic section 72 extending proximally fromthe fastener housing 10. A handle section 74 is attached at the proximalend of the elongated endoscopic section 72.

The materials utilized in the elongated endoscopic section 72 and thehandle section 74 include such materials as polycarbonate for housingsections and related components, and stainless steel for such componentswhich transmit forces. One preferred polycarbonate material is LEXANbrand polycarbonate available from General Electric Company. Otherspecific preferred materials such as nylon or glass filled nylon (forstrength) are also utilized. However, equivalent alternative materialsmay be used.

It is also contemplated and within the scope of the invention toconstruct the endoscopic section 72 to be selectively detachable wherebythe handle section 74 may be sterilized and reused, or the endoscopicsection 72 can be sterilized, and the fastener housing 10 re-loaded withfasteners for re-use. Alternatively, a replacement fastener magazine maybe reloaded in the endoscopic section 72, and optionally a replacementendoscopic section 72 may be detachably secured to a disposable handle74 for multiple use during a single surgical procedure. Moreover, theinstrument shown may be entirely disposable. Thus, any combination ofalternatives may be incorporated within the scope of the invention.

Referring to FIG. 8, there is shown a preferred handle section 74 of theinstrument 70 with associated components. The handle section 74 includesan outer housing preferably formed of a polycarbonate material inseparate sections as shown. The separate sections are attached, forexample, by welding, adhesives, etc. One purpose of the handle section74 is to provide controlled distal movement of the pusher means and morespecifically, the pusher element 46 at the distal end of the pusher bar38, a portion of which is shown in FIG. 6.

The handle section 74 of the endoscopic surgical instrument 70 includesa handle grip 76 and a pivotal handle trigger mechanism 78 which ispivoted toward and away from the handle grip 76. The trigger mechanism78 is pivoted toward the handle grip 76 during the fastener advancingand firing sequence which will be described in further detail below. Thehandle trigger mechanism 78 pivots away from the grip 76 to return theinstrument 70 to the pre-fired condition in position for firing the nextfastener.

As shown in FIGS. 6 and 13, the pusher bar 38 preferably extends throughthe elongated endoscopic section 72. The endoscopic section 72 isrotatably attached to the handle section 74 via a rotatable noseassembly 77 having a bottom cover plate 78, shown in FIGS. 7-9. Therotatable nose assembly 77 is adapted to rotate the entire endoscopicsection 72 a full 360 degrees as will be described hereinbelow. Further,a barrel portion 80 is integral with the rotatable nose assembly 77 andis configured and dimensioned for receiving a thrust bar assembly 82.

Referring back to FIG. 8 thrust bar assembly 82 includes a thrust bar 84connected to the pusher bar 38 shown in FIG. 6. The thrust bar 84 has aridge 86 at its distal end for mating with a hole 88 at the proximal endof the pusher bar 38 shown in FIG. 13 and more fully described below.The hole 88 is slightly larger than the ridge 86 of the thrust bar 84 toprovide longitudinal movement of the ridge 86 within the hole 88. Theoversized hole 88 provides a small degree of relative movement betweenthe thrust bar assembly 82 and the pusher means. This small degree ofmovement provides several advantages. For example, minor proximalmovements of the trigger mechanism 78 will not immediately result inengagement between the pusher means and the next available fastener,thus avoiding inadvertent distal movement of the fastener duringhandling by operating room personnel or positioning by the user. Alsoengagement of the pusher bar 38 with the next fastener will not occuruntil the pawl and ratchet plate of the clutch mechanism 106 (describedbelow) takes place, thus preventing inadvertent partial advancement ofseveral fasteners at a time. This would occur if the operator wereallowed to partially activate the trigger mechanism 78 several timesover the same part of its cycle. The clutch mechanism 106 prevents suchmovements. Further, this free movement of the thrust bar 84 permits thefastener advancing and forming components to engage each other smoothlywithout jamming or intercomponent interference with themselves.

A curved link 90 is pivotably connected at a lower portion to thetrigger mechanism 78 by a proximal shaft 92. The trigger mechanism 78 ispivotally attached to the handle grip 76 by an upper pivot pin 94, thusproviding for pivotal movement towards and away from the handle grip 76.Movement of the trigger 78 towards the grip 76 produces rotationalmovement of the curved link 90 because the shaft 92 traverses an upwardarc whose center of rotation is located at the upper pivot pin 94.

An upright member 96 is pivotably attached towards its upper end byshaft 98 to the upper portion of the curved link 90. The upright memberis also pivotably attached towards its lower end by pin 100 to thehandle grip 76, as shown in FIG. 8. Since the upright member 96 ispivotably attached at upper and lower points 98, 100 respectively, therotational motion of the curved link produces longitudinally directeddistal and proximal motion of the upright member 96.

Thrust bar assembly 82 is connected to upright member 96 through anaperture 33 in the upright member 96 such that the inward squeezing oftrigger mechanism 78 will cause the entire thrust bar assembly 82 toadvance distally against the constant force provided by the spring 102.The spring 102 is normally biased in the coiled configuration. One endof the spring 102 is attached to a spring nub 104 at the upper end ofthe upright member 96, and the other end is attached to the handle grip76 by post 105.

It can therefore be appreciated that after squeezing the triggermechanism 78 the full stroke from the at rest position to the actuatedposition, release of the trigger mechanism 78 will permit the spring 102to assume control and to return to the pre-fired original unloadedconfiguration. This motion in turn causes the entire thrust bar assembly82 to return to the proximal most pre-fired position.

Referring now to FIGS. 8-12, the structure and function of the preferreduni-motion clutch mechanism 106 will be described. The clutch mechanism106 prevents proximal movement of the thrust bar assembly not shown inFIGS. 9-12 in the event the trigger mechanism 78 is released after thesqueezing motion of the trigger mechanism 78 and the advancement of thethrust bar assembly not shown in FIGS. 9-12 has begun, but before thefull stroke is completed. The clutch mechanism 106 is self-releasingwhen the thrust bar assembly not shown in FIGS. 9-12 reaches the distalmost position, thus permitting the entire thrust bar assembly not shownin FIGS. 9-12 to return to the pre-fired, or proximal most condition,and the trigger mechanism 78 to also return to the pre-fired position.

A ratchet plate 108 is fixed to the barrel 80 and includes a pluralityof right angle triangular shaped parallel ridges 110. A pawl 112 isrockably mounted for distal and proximal movement with the thrust barassembly 82 and is biased toward the ratchet plate 108 by a resilientwire spring 114 as shown. Pawl 112 is preferably formed of stainlesssteel while the ratchet plate 108 is preferably made of brass or othercomparable material.

When the trigger mechanism 78 is squeezed toward the handle grip 76producing distal motion of the entire thrust bar assembly 82, the pawl112 engagably slides distally past the ratchet surface 56 of the ratchetplate 52 as shown in FIG. 11 such that one corner of the tip 62 of thepawl 112 sequentially engages each right angled ridge of the ratchetplate 52 to thereby prevent proximal movement of the thrust bar assembly82 in the event the trigger mechanism 78 is released by the operator.The engagement of the pawl 112 with the ratchet plate 108 providesaudible confirmation that the pusher assembly is moving distally sincethe user will hear a series of audible clicks. This action continueswith the tip 116 of pawl 112 sliding past the ratchet surface of theratchet plate 108 until the pawl 112 is positioned distally of thedistal most ridge.

After completion of the fastener firing stroke and upon release of thetrigger mechanism 78, the pawl 112 moves proximally with the thrust barassembly 82 under the action of the spring 102 as described above. Thetip 116 of the pawl 112 which is now free, engages the distal end of theratchet plate 108 causing the pawl 112 to rock to the reverse directionshown in FIG. 12 so as to slide proximally past the ratchet surface ofthe ratchet plate 108 without interference to the proximal movement ofthe thrust bar assembly 82.

Referring to FIGS. 8-12, when the handle grip 76 is positioned in thepalm of the user's hand and the trigger mechanism 78 is squeezed towardthe handle grip 76, the pin 92 of the trigger travels in a generallyupward direction pushing the curved link 90 upwardly and distally in agenerally counterclockwise direction. Simultaneously, the upright member35, to which the curved link is attached via pivot point pin 98 in theupper portion of the curved link, pivots distally about the point ofrotation defined by the pivot pin 100 located at the lowermost end ofthe handle grip 76.

The upright member's distal movement approximates the thrust barassembly 82 distally and consequently moves the pusher bar 38 distally.As a result, the uni-motion clutch mechanism 106 is engaged as describedabove. The clutch mechanism 106 effectively permits squeezing thetrigger mechanism 78 toward the handle grip 76 while maintainingpositions midway through the stroke in the event the operator releasesthe grip, and permits return motion after the stroke has been completed.

The clutch mechanism 106 also allows the operator to advantageouslypreposition a fastener such that the legs of the fastener protrude fromthe distal end of the fastener housing 10 and then release pressure fromthe trigger mechanism 78. The operator may then turn full attention tolocating the prepositioned fastener in the desired target location, atwhich point the pivoting of the trigger mechanism 78 may be resumed andthe cycle completed. This fastener prepositioning greatly facilitatesfastener placement.

Although the preferred embodiment described herein and illustrated inthe accompanying drawings depicts a preferred technique, i.e. handlesection 74, for actuating the pusher means, other techniques havingassociated mechanisms and related structure may be employed.

Referring to FIG. 13, the elongated endoscopic section 72 is shown inexploded view with parts separated for convenience of illustration. Theendoscopic section 72 includes an upper housing half section 118 and alower housing half section 120. The housing half sections are preferablyof a polycarbonate material such as LEXAN brand material mentionedpreviously, and may be attached by welding, adhesives, etc.

The pusher bar 38 and the U-shaped pusher element 46 are positionedbetween the upper and lower housing half sections as described above andshown in FIG. 6. An anvil section 122, preferably formed of stainlesssteel, includes the anvil 26, as described above and shown in FIGS. 1and 6, and an elongated anvil portion 124 integral with the anvil andextending proximally from the anvil 26. The elongated anvil portionincludes upwardly extending feet 126 at its proximal end. The elongatedanvil portion 124 further includes an elongated slot 132 towards itsproximal end dimensioned and configured to slidably mate with the raisedportion 134 of the pusher bar 38 (described below).

The anvil 26 is positioned within the fastener housing 10 at the distalend of the instrument 70, as shown in FIG. 6 and 13. The proximalconnection points of the elongated anvil portion include upwardlyextending feet 126 which are engagable within slots in the rotatablenose assembly 77 of FIG. 9. Thus, the endoscopic portion of theinstrument 70 is positively connected to the handle section 74 by theupwardly extending feet 126 and is rotatable via the rotatable noseassembly 77.

The elongated anvil portion 88 stabilizes the dimension of theendoscopic section 72. The stabilizing effect prevents forces acting onthe components from stretching or compressing the upper and lowerhousing half sections 118, 120 of the endoscopic section 72. Thus, theelongated anvil portion provides dimensional stability to the endoscopicsection 72 while the endoscopic section 72 is supporting the componentsbeing subjected to forces for supporting, advancing, and forming thesurgical fasteners.

The upper housing half section 118 is generally semicircular in shapeand preferably includes a central groove 128 along its innerside forguiding a coiled main spring 164. Similarly, the lower housing halfsection 120 of the endoscopic section 72 is generally semicircular inshape and preferably includes a central groove 130 substantiallyidentical to the groove 128 for guiding a coiled main spring 164 inconcert with the groove 128 in the upper housing half section 118.

The pusher bar 38 includes a raised portion 134 at its proximal end. Theraised portion includes a hole 88 configured and dimensioned foraccepting the ridge 86 in the thrust bar assembly 82. The pusher element46 is connected at the distal end of the pusher bar 38.

A pusher shroud 136 is positioned at the distal end of the pusher bar 38and holds the pusher element 46 in place. The pusher element 46 in placeat the distal end of the pusher bar 38 is preferably a pusher shroud136. The pusher shroud 136 is connected to the bottom of the pusher bar38, for example, by welding or rivets. As described above and shown inFIGS. 4, 6 and 13, the pusher element 46 includes a pin 48 rotatablymating with an elongated opening 138 in the pusher bar 38 and advancesthe fasteners in the fastener housing 10 for application.

An ejector spring 140 is located in the fastener housing 10 and includesdownwardly projecting legs 141. The legs 141 are configured anddimensioned to position the fasteners advanced by the pusher element 46in an engagable position with the anvil 26 and provide the desired forceto assist in ejecting the fastener from the fastener housing after thefastener has engaged the anvil 26.

Attached to the bottom of the elongated anvil portion 124 is a guidelift spring 142 which is positioned between the elongated anvil portion124 and the pusher bar 38. A slot 144 in the guide lift spring 142includes an open distal end and partially overlaps the slot 18 in thefastener housing track 12. The guide lift spring 142 aligns the pusherelement 46 in the fastener housing track slot 18 by encouraging the pin48 of the pusher element 46 to communicate with the slot 144 in theguide lift spring 142. The pusher element 46 is thus guided by the openended slot 144 while advancing a fastener.

A front fastener plate 146 is positioned within the lower housing halfsection 120 and beneath the pusher bar 38. The distal end of thefastener front plate 146 is configured and dimensioned to align thefasteners and assist in positioning the fasteners as they are cuedforward by the fastener pusher. The front fastener plate includes at itsdistal end two distally extending prongs 148 and a downwardly extendingflap 150. A fastener fits between the two distally extending legs 148 ofthe front fastener plate 146 which are preferably part of a generallyU-shaped configuration formed at the distal end of the front fastenerplate 146. The flap 150 communicates with the crown of the fastener andassists in maintaining the faster in a desirable position for the pusherelement 46 to advance the fastener in the fastener housing 10.

Working in concert, the front fastener plate 146 and the lower housinghalf section 120 position the fasteners therebetween maintainingalignment of the fasteners as they are advanced by the fastener pusher156. Moreover, when the fastener pusher 156 approaches its distal mostposition, the downwardly extending flap 150 of the front fastener plate146 communicates with the top of the fastener pusher 156 to assist instabilizing the pusher 156 such that the fasteners continue in theappropriate path.

A rear fastener plate 152 communicates with the proximal end of thefront fastener plate 146 and extends proximally with respect to thefront fastener plate 146. The rear fastener plate 152 includes anelongated hole 154 which is configured and dimensioned to receive aupwardly extending tab 160 at the proximal end of a fastener pusher 156.

The fastener pusher 156 is slidably positioned between the rear fastenerplate 152 and the lower housing half section 120. The fastener pusher156 includes a pusher head 158 at its distal end having a generallyU-shaped tip and an upwardly extending tab 160 at its proximal end. Thepusher head 158 is dimensioned and configured to communicate with thecrown and legs of a fastener, thus providing positive interactionbetween the fastener and the fastener pusher 156.

An upwardly extending tab 160 is located at the proximal end of thefastener pusher 156, and a spring guide 162 is attached to the bottom ofthe fastener pusher 156 via conventional means, and extends generallydownward. The fastener pusher 156 is biased in the distal direction by acoiled main spring 164 communicating with the tab 160 and the springguide 162. Thus, a fastener or a plurality of fasteners may be biased inthe distal direction such that the fasteners may be sequentially fired.

The coiled main spring 164 is positioned within the groove 130 in thelower housing half section 120 and extends upwardly in a coiled fashionthrough the elongated hole 154, the elongated opening 138, and theelongated slot 132 to communicate with the groove 128 in the upperhousing half section 118. Thus, the coiled main spring 164 is guided bythe grooves 130, 128 in the upper and lower housing half sections 120,118. Spring 164 biases the fastener pusher 156 distally by communicatingwith the proximal side of the tab 160 and the spring guide 162.

A fastener feed plate 166 is positioned at the distal end of the lowerhousing half section 120 and includes two parallel distally extendingfeet 168. A portion of the feet 168 are inclined upwardly to advance afastener to a desired elevated position. More specifically, the feet 168are configured and dimensioned such that as a fastener is moving overthe fastener feed plate 166 in the distal direction the fastener iselevated upwardly as it advances over the feet 168.

A gas sealing means 170 includes a substantially circular body having anaperture therethrough. The gas sealing means 170 is positioned distallyto the rotatable nose assembly 77 and between the upper and lowerhousing half sections 118, 120. The gas sealing means 170 effects asubstantial internal seal within the endoscopic section 72 of theinstrument 70. The gas sealing means 170 is configured and dimensionedto accommodate longitudinal movement of the pusher bar 38 and thefastener pusher 156 while discouraging gasses used to insufflate thebody cavity from egressing through the endoscopic section 72. Althoughthe gas sealing means 170 is designed as described above and as shown inthe accompanying drawings, it is contemplated that other gas sealingmeans having different configurations may be used.

It is also contemplated that the fastener feed plate 166 described aboveand illustrated in the accompanying drawings may be configured anddimensioned differently, while providing the specified elevation of thefastener in a similar fashion to fastener feed plate 166.

A lubricant may be used on or about any of the internal parts discussedabove in the handle section 74 or the endoscopic section 72 of theinstrument, such as between a moving part and a non-moving part, orbetween two moving parts. Lubricant may be used, for example, betweenthe lower housing half section 120 and the pusher bar 38 and/or thefastener pusher 156. The lubricant is used for reducing frictionalresistance and providing smooth interaction between the parts. Adesirable lubricant may be, for example, a lithium grease, or a siliconegrease.

In operation, after the endoscopic section 72 enters the body cavityinsufflated with gas, the sealing means 170 impedes deflation of thebody cavity by discouraging gasses from escaping past the endoscopicsection 72. Next, as the handle trigger mechanism 78 is pulled towardsthe handle grip 76, the pusher bar 38 is actuated distally by theinteraction between the thrust bar 84 connected to the pusher bar 38 byridge 86. The pusher element 46 attached to the pusher bar 38 via pin 48advances a fastener already in position in the fastener housing 10. Thefastener is applied by engagement with the anvil 26 as described above.

After a fastener is applied, a vacancy in the fastener housing 10 isfilled by another fastener biased to move distally by the coiled mainspring 164 positioned proximal the fastener pusher 156. A fastener ismoved to assume the ready position in the fastener housing 10 by thefastener pusher 156 advancing the fastener with the pusher head 158. Aplurality of fasteners may be positioned proximal the fastener pusher156 and can be biased in the distal direction by interaction with thepusher head 158 of the fastener pusher 156.

The fastener is moved upwardly from communicating with the fastenerpusher 156 to being positioned for engagement with the anvil 26 via thefastener feed plate 166. As the fastener progresses over the fastenerfeed plate 166 in the distal direction, the fastener is elevatedupwardly as it advances over the feet 168. The front fastener plate 146assists in positioning the fastener for distal movement for advancementby the pusher element 46 by accommodating the fastener with itsgenerally U-shaped distal end. As the fastener pusher 156 approaches itsdistal-most position, the downwardly extending flap 150 of the frontfastener plate 146 communicates with the top of the fastener pusher 156,thereby stabilizing the pusher 156 such that the fasteners continue intheir appropriate path. Thus, the interaction of the fastener pusher156, the front fastener plate 146, and the pusher element 46 enablesequential application of fasteners.

Although the pusher head and the distal end of the front fastener platehave generally U-shaped configurations in the preferred embodimentdescribed herein and shown in the accompanying drawings, other shapesmay be desirable.

Further, other means having related structure to that shown in thepreferred embodiment described herein and illustrated in theaccompanying drawing may be used to advance fasteners sequentially.

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the invention,but nearly as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the invention as defined by the claimsappended hereto.

What is claimed is:
 1. A surgical instrument for placing a fastener inor on tissue comprising:(a) a fastener housing having anvil meansmounted at one end thereof and adapted to house at least one fastenertherein; (b) pusher means slidably received by said fastener housing,said pusher means comprising a pusher bar which defines a longitudinalaxis and a pusher element slidably mounted to said pusher bar; (c) slotmeans in said fastener housing, wherein said pusher means cooperateswith said slot means to angularly displace said pusher element withrespect to said longitudinal axis as said pusher means is advancedthrough said fastener housing; and d) means for actuating said pushermeans being positionable proximal of said fastener housing.
 2. Thesurgical instrument of claim 1, wherein said means for actuating furthercomprises:an elongated endoscopic section extending proximally from saidfastener housing and substantially encasing said pusher means; and ahandle section couplable with said elongated endoscopic means at anopposite end from said fastener housing, said handle section cooperatingwith said pusher means to manually and selectively activate said pushermeans.
 3. The surgical instrument of claim 2 wherein said elongatedendoscopic section includes a rotatable portion positioned distally fromsaid handle section.
 4. The surgical instrument of claim 2 wherein saidelongated endoscopic section is configured and adapted for insertioninto endoscopic tubular means.
 5. The surgical instrument of claim 2,further comprising means for preventing proximal movement of said pushermeans after said pusher means has moved distally a predetermined amount.6. The surgical instrument of claim 2 further comprising gas sealingmeans to prevent gases from egressing through the endoscopic portion. 7.A fastener-forming assembly comprising:(a) a fastener housing defining afastener track having a center line and an opening at one end adapted topermit fastener exit, said fastener housing further including pushermeans disposed therein; (b) anvil means positioned adjacent saidopening, said anvil means being positioned in a transverse andnon-symmetrical orientation with respect to said center line; (c) afastener having a backspan and a pair of legs extending from thebackspan at either end thereof; wherein contact of said fastener withsaid non-symmetrically positioned anvil causes said backspan of saidfastener to bend such that said fastener legs assume a substantiallyover-lapping, longitudinally-spaced relation; and (d) means foractuating said pusher means, said means for actuating being positionableproximal of said fastener housing.
 8. The surgical instrument of claim7, wherein said means for actuating further comprises:an elongatedendoscopic section extending proximally from said fastener housing andsubstantially encasing said pusher means; and a handle section couplablewith said elongated endoscopic means at an opposite end from saidfastener housing, said handle section cooperating with said pusher meansto manually and selectively activate said pusher means.
 9. The surgicalinstrument of claim 8 wherein said elongated endoscopic section includesa rotatable portion positioned distally from said handle section. 10.The surgical instrument of claim 8 wherein said elongated endoscopicsection is configured and adapted for insertion into endoscopic tubularmeans.
 11. The surgical instrument of claim 8, further comprising meansfor preventing proximal movement of said pusher means after said pushermeans has moved distally a predetermined amount.
 12. The surgicalinstrument of claim 8 further comprising gas sealing means to preventgases from egressing through the endoscopic portion.